Brake



H. F. PARKER BRAKE Filed May 17, 1950 x m m w.

HUMPHREY F. PARKER A TTORNEY Patented May 21, 1935 BRAKE Humphrey F. Parker, South to Bendix Brake Company, a corporation of Illinois Bend, Ind., assignor South Bend, Ind.,

Application May 1'], 1930, Serial No. 453,385

11 Claims.

This invention relates to brakes and more particularly to internal expanding. brakes.

A major object of the invention is to provide a brake structure in which smoothness of operation is attained.

An important object of the invention is to provide a brake structure in which the load is evenly distributed.

Another object of the invention is to provide a brake structure in which grabbing of the friction elements is avoided.

An important feature of the invention is the structure of the friction elements which maintain the applied force fairly constant over the entire braking surface.

Another feature of the invention is the assempart of this specification, and in which:

Figure 1 is a sectional .view taken just back of the disc of the drum, illustrating the invention as applied; and

Figure 2 is a similar view illustrating a modifled form.

Referring to the drawing for more specific details of the invention, .lli represents a flxed support such as a backing plate having associated therewith a rotatable drum I I. As shown, the backing plate has positioned thereon, anchors l2 and I3, and an actuating cam I l mounted on a shaft l5 positioned for rotation on the backing plate.

Positioned for movement on the backing plate is a primary shoe IS, a secondary shoe l1 and an auxiliary shoe I8. 'The auxiliary shoe l8 has an extended heel portion l9 pivoted on the anchor l3. As shown, the extended heel portion curves abruptly from and is a continuation of the web of the shoe so that a greater leverage may be attained. The secondary shoe l'l comprises a substantially flexible band having thereon an arm 10 which is spaced from the heel of the shoe to provide a cantilever effect. The arm 20 is curved from the shoe so, that its connection with the anchor I2 is substantially opposite the heel of the shoe.

' The toe of the secondary shoe has a flange portion 2| spaced from the toe, and to this flange portion is pivoted the heel of the primary shoe by an extended portion 22 which is in effect a continuation of the web. As shown, the primar' and auxiliary shoes are provided with thrust rollers 23 and Mengaging the respective sides of the cam l4, and suitable return springs 25 and 10 '26 are provided for returning and retaining the shoes in proper spaced relation to the drum When the brake is released and isin off position.

It is to be observed by this assembly of relatively rigid shoes, together with a substantially flexible shoe, a more uniform engagement of the shoes and hence an even distribution of the load may be attained. It is further to be observed that by the reason of the cantilever effect produced by the extended'webs of the primary and auxiliary shoes and by reason of the particular location of the arms on the flexible shoe, liability of the heel digging in the radius of the drum and causing a grabbing and chattering of the friction elements, is avoided. Hence, 25 it is apparent that a brake embodying the structure herein set forth will be exceedingly smooth in operation.

In the modified form of the invention shown, the principles involved in the preferred form have been applied to a hand brake. In this modification of the invention, a band 21 of any preferred type is provided with short web sections 28, spaced from the separable ends of the friction elements, so that in effect a cantilever is provided at the respective ends of the band. As shown, the web portions 28 are connected by a toggle 29 which in turn is connected through a link to a crank 3! 'on an operating shaft 32 positioned for rotation in the backing plate.

The web sections 28 are connected by a suitable coil spring 83 and connecting the band to the backing plate is a coil spring 34. These springs serve to return and retain the band in proper spaced relation to the drum when the brake is in. the off position.

The salient feature of this invention is the particular arrangement of two relatively rigid shoes with one substantially flexible shoe and the relative position of the anchoring and connecting means of these shoes with relation to the heels and toes of the shoes which provides an ideal structure in which grabbing of the shoe is prevented and an even distribution of the load is attained.

Although this invention has been described in connection with certain specific embodiments, the principlesinvolved are susceptible to numerous other applications that will readily occur to persons skilled in the art. The invention is, thereiore, limited only as indicated by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent, is:

1. A brake comprising a plurality of friction elements each having its own anchor and at least one of the elements having a radially-yieldable extended flexible heel projecting past the anchor of the adjacent element.

2. A brake comprising two relatively rigid friction elements and a relatively flexible friction element associated therewith and having an anchor arm overlapping the end of one of the rigid elements, means through which the other rigid element acts on the flexible element, and anchors for the arm and the overlapped end of said one of the rigid elements.

3. A brake comprising a fixed support, a plurality of shoes positioned for movement on the support, including two rigid shoes and a shoe having flexible end portions positioned between the rigid shoes with its flexible end portions overlapping the ends of the rigid shoes, and means for actuating the shoes.

4. A brake comprising a fixed support, a r0- tatable drum associated therewith, a plurality of shoes positioned for movement on the. support including a rigid primary shoe, a secondary shoe and a rigid auxiliary shoe, and means for spreading the shoes for engagement with the drum, the secondary shoe having a flexible end portion overlapping the end oi one of the rigid shoes.

5. A brake comprising a fixed support, a plurality of shoes positioned for movement on the support including a rigid primary shoe, a flexible secondary shoe having a free end portion and an auxiliary shoe, and means positioned between the primary shoe and the auxiliary shoe for spreading the shoes for engagement with the drum, one of the shoes having an anchor past which the free end portion or the secondary shoe projects.

6. A brake comprising two relatively short rigid friction elements, a relatively long flexible friction element having an arm and an extended fiexible heel, a web on the flexible element in spaced relation to the toe, the heel on one of the rigid elements and the arm on the flexible element being pivotally supported, and the web on the flexible member being pivotally connected to the heel of the other rigid element.

7. A brake comprising a fixed support, a rotatable drum associated therewith, a plurality of shoes positioned for movement on the support including a primary shoe, a secondary shoe and an auxiliary shoe, the primary shoe being pivoted to the secondary shoe in spaced relation from the toe thereof, the secondary shoe being anchored by an arm extending from the rim thereof in spaced relation to the heel of the shoe, and the auxiliary shoe anchored to the support adjacent to the anchor for the secondary shoe and a cam between the primary and auxiliary shoes for spreading the shoes in engagement with the drum.

8. A brake shoe having a substantially flexible body and a curved anchor arm projecting from an intermediate portion of said body and having its ends formed with a bearing for an anchor pivot and arranged radially inside of and approximately in line with the end of the flexible body.

9. A brake comprising a drum, anchorage means adjacent one side of the drum, and a friction member having one part anchoring on said means when the drum is turning in one direction and another part anchoring on said means when the drum is turning in the other direction and having flexible end portions of substantial length projecting past the anchorage means.

10. A brake comprising a drum, anchorage means adjacent one side of the drum, and a substantially flexible friction stiffened part anchoring on said means when the drum is turning in one direction and another stiffened part anchoring onsaid means when the drum is turning in the other direction and having flexible end portions of substantial length projectlng past the anchorage means.

11. A brake comprising a drum, anchorage means adjacent one side of the drum, and a friction member having one part anchoring on said means when the drum is turning in one direction and another part anchoring on said means when the drum is turning in the other direction and having at least one flexible end portion of substantial length projecting past the anchorage means.

I. PARKER.

band having one, 

